refactor: extract shared dep parser to lib/parse-deps.py (Closes #20)

Single source of truth for dependency parsing, replacing three copies:
- dev-poll.sh get_deps() now calls parse-deps.py
- supervisor P3b/P3c import parse_deps() via importlib

Supports stdin, argument, and --json modes for different callers.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

dev/dev-poll.sh

@@ -115,18 +115,8 @@ dep_is_merged() {
 # =============================================================================
 get_deps() {
   local issue_body="$1"
-  # Extract #NNN references from "Depends on" / "Blocked by" sections
-  # Capture the header line AND subsequent lines until next ## section
-  {
-    echo "$issue_body" | awk '
-      BEGIN { IGNORECASE=1 }
-      /^##? *(Depends on|Blocked by|Dependencies)/ { capture=1; next }
-      capture && /^##? / { capture=0 }
-      capture { print }
-    ' | grep -oP '#\K[0-9]+' || true
-    # Also check inline deps on same line as keyword
-    echo "$issue_body" | grep -iE '(depends on|blocked by)' | grep -oP '#\K[0-9]+' || true
-  } | sort -un
+  # Shared parser: lib/parse-deps.py (single source of truth)
+  echo "$issue_body" | python3 "${FACTORY_ROOT}/lib/parse-deps.py"
 }
 
 # =============================================================================

lib/parse-deps.py

@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+"""Extract dependency issue numbers from an issue body.
+
+Usage:
+    echo "$ISSUE_BODY" | python3 lib/parse-deps.py
+    python3 lib/parse-deps.py "$ISSUE_BODY"
+    python3 lib/parse-deps.py --json < issues.json
+
+Modes:
+    stdin/arg:  reads a single issue body, prints one dep number per line
+    --json:     reads a JSON array of issues from stdin, prints JSON
+                dep graph: {"issue_num": [dep1, dep2], ...}
+
+Matches the same logic as dev-poll.sh get_deps():
+  - Sections: ## Dependencies / ## Depends on / ## Blocked by
+  - Inline: "depends on #NNN" / "blocked by #NNN" anywhere
+  - Ignores: ## Related (safe for sibling cross-references)
+"""
+import json
+import re
+import sys
+
+
+def parse_deps(body):
+    """Return sorted list of unique dependency issue numbers from an issue body."""
+    deps = set()
+    in_section = False
+    for line in (body or "").split("\n"):
+        if re.match(r"^##?\s*(Depends on|Blocked by|Dependencies)", line, re.IGNORECASE):
+            in_section = True
+            continue
+        if in_section and re.match(r"^##?\s", line):
+            in_section = False
+        if in_section:
+            deps.update(int(m) for m in re.findall(r"#(\d+)", line))
+        if re.search(r"(depends on|blocked by)", line, re.IGNORECASE):
+            deps.update(int(m) for m in re.findall(r"#(\d+)", line))
+    return sorted(deps)
+
+
+if __name__ == "__main__":
+    if len(sys.argv) > 1 and sys.argv[1] == "--json":
+        issues = json.load(sys.stdin)
+        graph = {}
+        for issue in issues:
+            num = issue["number"]
+            deps = parse_deps(issue.get("body", ""))
+            deps = [d for d in deps if d != num]
+            if deps:
+                graph[num] = deps
+        json.dump(graph, sys.stdout)
+        print()
+    else:
+        if len(sys.argv) > 1:
+            body = sys.argv[1]
+        else:
+            body = sys.stdin.read()
+        for dep in parse_deps(body):
+            print(dep)

supervisor/supervisor-poll.sh

@@ -297,33 +297,22 @@ status "P3: checking for circular dependencies"
 BACKLOG_FOR_DEPS=$(codeberg_api GET "/issues?state=open&labels=backlog&type=issues&limit=50" 2>/dev/null || true)
 if [ -n "$BACKLOG_FOR_DEPS" ] && [ "$BACKLOG_FOR_DEPS" != "null" ] && [ "$(echo "$BACKLOG_FOR_DEPS" | jq 'length' 2>/dev/null || echo 0)" -gt 0 ]; then
 
+  PARSE_DEPS="${FACTORY_ROOT}/lib/parse-deps.py"
+
   CYCLES=$(echo "$BACKLOG_FOR_DEPS" | python3 -c '
-import sys, json, re
+import sys, json, importlib.util
+
+spec = importlib.util.spec_from_file_location("parse_deps", sys.argv[1])
+mod = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(mod)
 
 issues = json.load(sys.stdin)
-
-def parse_deps(body):
-    deps = set()
-    in_section = False
-    for line in (body or "").split("\n"):
-        if re.match(r"^##?\s*(Depends on|Blocked by|Dependencies)", line, re.IGNORECASE):
-            in_section = True
-            continue
-        if in_section and re.match(r"^##?\s", line):
-            in_section = False
-        if in_section:
-            deps.update(int(m) for m in re.findall(r"#(\d+)", line))
-        if re.search(r"(depends on|blocked by)", line, re.IGNORECASE):
-            deps.update(int(m) for m in re.findall(r"#(\d+)", line))
-    return deps
-
 graph = {}
 for issue in issues:
     num = issue["number"]
-    deps = parse_deps(issue.get("body", ""))
-    deps.discard(num)
+    deps = [d for d in mod.parse_deps(issue.get("body", "")) if d != num]
     if deps:
-        graph[num] = deps
+        graph[num] = set(deps)
 
 WHITE, GRAY, BLACK = 0, 1, 2
 color = {n: WHITE for n in graph}
@@ -352,7 +341,7 @@ for cycle in cycles:
     if key not in seen:
         seen.add(key)
         print(" -> ".join(f"#{n}" for n in cycle))
-' 2>/dev/null || true)
+' "$PARSE_DEPS" 2>/dev/null || true)
 
   if [ -n "$CYCLES" ]; then
     while IFS= read -r cycle; do
@@ -367,36 +356,24 @@ for cycle in cycles:
   status "P3: checking for stale dependencies"
 
   STALE_DEPS=$(echo "$BACKLOG_FOR_DEPS" | CODEBERG_TOKEN="$CODEBERG_TOKEN" CODEBERG_API="$CODEBERG_API" python3 -c '
-import sys, json, re, os
+import sys, json, os, importlib.util
 from datetime import datetime, timezone
 from urllib.request import Request, urlopen
 
+spec = importlib.util.spec_from_file_location("parse_deps", sys.argv[1])
+mod = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(mod)
+
 issues = json.load(sys.stdin)
 token = os.environ.get("CODEBERG_TOKEN", "")
 api = os.environ.get("CODEBERG_API", "")
 issue_map = {i["number"]: i for i in issues}
 now = datetime.now(timezone.utc)
 
-def parse_deps(body):
-    deps = set()
-    in_section = False
-    for line in (body or "").split("\n"):
-        if re.match(r"^##?\s*(Depends on|Blocked by|Dependencies)", line, re.IGNORECASE):
-            in_section = True
-            continue
-        if in_section and re.match(r"^##?\s", line):
-            in_section = False
-        if in_section:
-            deps.update(int(m) for m in re.findall(r"#(\d+)", line))
-        if re.search(r"(depends on|blocked by)", line, re.IGNORECASE):
-            deps.update(int(m) for m in re.findall(r"#(\d+)", line))
-    return deps
-
 checked = {}
 for issue in issues:
     num = issue["number"]
-    deps = parse_deps(issue.get("body", ""))
-    deps.discard(num)
+    deps = [d for d in mod.parse_deps(issue.get("body", "")) if d != num]
     for dep in deps:
         if dep in checked:
             dep_data = checked[dep]
@@ -423,7 +400,7 @@ for issue in issues:
                 print(f"#{num} blocked by #{dep} \"{dep_title}\" (open {age_days} days)")
         except Exception:
             pass
-' 2>/dev/null || true)
+' "$PARSE_DEPS" 2>/dev/null || true)
 
   if [ -n "$STALE_DEPS" ]; then
     while IFS= read -r stale; do